Reinhard Fries

A cross-sectional study of Salmonella in pre-slaughter pigs in a production compartment of northern Thailand.

A cross-sectional study was conducted to determine the prevalence of Salmonella and to associate management factors in fattening pigs in a production compartment of northern Thailand. A total of 194 fecal samples and 166 environmental samples were collected from 22 fattening pig herds for isolation and identification of Salmonella. An additional 427 serum samples were collected from the same herds to determine Salmonella antibodies using ELISA. A questionnaire was used to collect management factors likely to be associated with Salmonella identification. Prevalence of Salmonella in each sample and its confidence interval was adjusted for clustering by herds using linearization technique. A generalized estimating equation was used to determine the odds ratio and significance level for each management factor in a logistic regression model. Salmonella was found in all 22 study pig herds with a fecal sample prevalence of 63% (95%CI: 56-69%) and a serum sample prevalence of 72%. However, isolation results were not significantly different from ELISA results. The most isolated serotype was Salmonella Rissen (49%) followed by Salmonella Typhimurium (19%), Salmonella Stanley (12%) and Salmonella Weltevreden (4%) being significantly different in the different specimens collected (p=.024). The final logistic regression model with isolation results as outcome showed that medium herd size (OR=2.32, p=0.003), quality certification according to the Department of Livestock Development standard (OR=1.88, p=0.000), use of effective microorganisms (OR=1.51, p=0.022), slurry waste management (OR=2.17, p=0.000) and less number of pigs per pen (OR=1.12, p=0.000) were significantly associated with positive Salmonella isolation; with positive ELISA results, however, only the use of effective microorganisms was significantly associated (OR=2.63, p=0.011).

A Cross-Sectional Study of Salmonella in Pork Products in Chiang Mai, Thailand

The occurrence of Salmonella in food of animal origin in Chiang Mai province was investigated by using a cross-sectional study during several phases of the pork production chain (cutting, transport, and retail) and of the environment in the cutting unit of a slaughterhouse. In total, 173 pork samples were obtained during the cutting phase, 173 samples from transported pork, 200 samples from retail products, and 300 samples from the slaughterhouse environment. Salmonella was detected in 55.5% of freshly cut pork, 70.5% of transported pork, and 34.5% of retail products. The five most prevalent Salmonella serotypes identified were Rissen (45.3%), Typhimurium (16.3%), Krefeld (10.6%), Stanley (6.3%), and Lagos (6.0%). Carcass contamination prior to cutting and in the slaughterhouse environment appeared to be important sources of Salmonella in transported pork and retail products. As Salmonella was also found during early stages of the slaughter process, attention should focus on all stages of the pork production chain to reduce contamination level and consumer risk of infection.

Isolation of Multidrug-Resistant Escherichia coli O157 from Goats in the Somali Region of Ethiopia: A Cross-Sectional, Abattoir-Based Study

Toxigenic Escherichia coli (E. coli) are an important cause of gastroenteritis in developing countries. In Ethiopia, gastroenteritis due to food-borne disease is a leading cause of death. Yet, there is no surveillance for E. coli O157 and little is known about the carriage of this pathogen in Ethiopia’s livestock. This study aimed to assess the prevalence and levels of antimicrobial resistance of E. coli O157 in goat meat, feces, and environmental samples collected at a large abattoir in the Somali region of Ethiopia. The samples were enriched in modified tryptone broth containing novobiocin, and plated onto sorbitol MacConkey agar. Isolates were confirmed using indole test and latex agglutination. Antimicrobial susceptibility testing was conducted using the disk diffusion method. A total of 235 samples, including 93 goat carcass swabs, 93 cecal contents, 14 water, 20 hand, and 15 knife swabs were collected. Overall, six (2.5%) samples were contaminated with E. coli O157 of which two (2.1%) were isolated from cecal contents, three (3.2%) from carcass swabs, and one (7.1%) from water. All isolates were resistant to at least two of the 18 antimicrobials tested. Two isolates (33.3%) were resistant to more than five antimicrobials. Abattoir facilities and slaughter techniques were conducive to carcass contamination. This study highlights how poor hygiene and slaughter practice can result in contaminated meat, which is especially risky in Ethiopia because of the common practice of eating raw meat. We detect multi-resistance to drugs not used in goats, suggesting that drugs used to treat human infections may be the originators of antimicrobial resistance in livestock in this ecosystem. The isolation of multidrug-resistant E. coli O157 from goats from a remote pastoralist system highlights the need for global action on regulating and monitoring antimicrobial use in both human and animal populations.

Autonomous Nervous System with Respect to Dressing of Cattle Carcasses and Its Probable Role in Transfer of PrP^r^e^s Molecules

Pathogen prions are widely recognized as the causative agent in bovine spongiform encephalopathy (BSE) and other transmissible spongiform encephalopathies. However, more research on the possible transmission mutes of this agent once it has reached the host is needed. There is evidence based on the anatomy and physiology of the autonomous nervous system (ANS), as well as observations for different animal species, that the ANS might be involved in the axonal drainage of pathogen prions toward the central nervous system. In this context, more attention should be paid to the cranial cervical ganglion, the stellate ganglion, the chain of paravertebral ganglia next to the first six thoracic vertebrae, the chain of the paravertebral ganglia next to loin vertebrae 1 through 6, the vagus nerve in the neck region and in the mediastine, and the esophagus (because of its close connection to the vagus nerve). For a more detailed risk analysis with respect to these tissues, the ANSs of animals having shown clinical signs of BSE might be examined to corroborate the evidence presented here. In the meantime, as a precautionary measure, the tissue addressed should be taken out of the human food chain, taken out of animal feed, and handled as if it were specified risk material. It is technically possible to remove these parts during cutting and dressing.

Quantification of water as a potential risk factor for cross-contamination with Salmonella, Campylobacter and Listeria in a poultry abattoir.

Abstract 1. Water used in a modern poultry processing line was tested from October 2005 to June 2006 to determine the level of bacteria in an abattoir in Germany. 2. A total of 420 water samples were taken from 14 processing sites (PSs), at 10 times, and from three different hours of the working shift at three sampling hours (SHs) at 5:00 a.m. (SH 1), 9:00 a.m. (SH 2) and 12:00 a.m. (SH 3). Each sample was assessed for the aerobic plate count (APC) and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia over 30 sampling weeks. The APC numbers of each PS from three SHs were compared, and the prevalence of Salmonella, Campylobacter, Listeria and Yersinia from each PS of three SHs was determined as well as change from the initial PS to the end of the processing line. 3. A total of 46 water samples were positive for Salmonella, 120 positive for Campylobacter and 4 positive for Listeria. None of the water samples was found to be positive for Yersinia. During the course of the day, the APC increased. Salmonella was mostly found during SH 1 (5 a.m.) in water from all PSs. A high number of Campylobacter were observed at SH 2 (9 a.m.) and SH 3 (12 a.m.) from all PSs. 4. The results show that water, which is still used in substantial amounts in present poultry processing technology, can serve as a carrier for Salmonella and Campylobacter. 5. The findings indicate that birds might progressively contaminate the equipment and become contaminated via the same equipment, that water at every processing position of the line constitutes a risk and that more attention should be paid to effective water management in the processing plan.

Prevalence and Antimicrobial Resistance of Salmonella Isolates from Chicken Carcasses in Retail Markets in Yangon, Myanmar

A cross-sectional investigation was conducted concerning prevalence, antimicrobial resistance, multidrug resistance patterns, and serovar diversity of Salmonella in chicken meat sold at retail in Yangon, Myanmar. The 141 chicken meat samples were collected at 141 retail markets in the Yangon Region, Myanmar, 1 November 2014 to 31 March 2015. Information on hygienic practices (potential risk factors) was retrieved via checklists. Salmonella was isolated and identified according to International Organization for Standardization methods (ISO 6579:2002) with minor modifications. Twelve antimicrobial agents belonging to eight pharmacological groups were used for antimicrobial susceptibility testing (disk diffusion method). Salmonella was recovered from 138 (97.9%) of the 141 samples. The isolates were most frequently resistant to trimethoprim-sulfamethoxazole (70.3% of isolates), tetracycline (54.3%), streptomycin (49.3%), and ampicillin (47.1%). Resistance was also found to chloramphenicol (29.7%), amoxicillin-clavulanic acid (17.4%), ciprofloxacin (9.4%), tobramycin (8.7%), gentamicin (8%), cefazolin (7.2%), lincomycin-spectinomycin (5.8%), and norfloxacin (0.7%). Among the 138 Salmonella isolates, 72 (52.2%) were resistant to three or more antimicrobial agents. Twenty-four serovars were identified among the 138 Salmonella-positive samples; serovars Albany, Kentucky, Braenderup, and Indiana were found in 38, 11, 10, and 8% of samples, respectively. None of the potential risk factors were significantly related to Salmonella contamination of chicken carcasses. This study provides new information regarding prevalence and antimicrobial resistance and Salmonella serovar diversity in retail markets in Yangon, Myanmar.

First report of the occurrence of Trichinella-specific antibodies in domestic pigs in Central and Eastern Uganda

Previous research on trichinellosis in Africa focused on isolating Trichinella from wildlife while the role of domestic pigs has remained highly under-researched. Pig keeping in Uganda is historically recent, and evidence on zoonotic pig diseases, including infection with Trichinella species, is scarce. A cross-sectional survey on Trichinella seroprevalence in pigs was conducted in three districts in Central and Eastern Uganda from April 2013 to January 2015. Serum from a random sample of 1125 pigs from 22 villages in Eastern and Central Uganda was examined to detect immunoglobulin G (IgG) against any Trichinella spp. using a commercially available ELISA based on excretory-secretory antigen. ELISA positive samples were confirmed using Western Blot based on somatic antigen of Trichinella spiralis as recommended in previous validation studies. Diaphragm pillar muscle samples (at least 5 g each) of 499 pigs from areas with high ELISA positivity were examined using the artificial digestion method. Overall, 78 of all 1125 animals (6.9%, 95% CI: 5.6–8.6%) tested positive for antibodies against Trichinella spp. in the ELISA at significantly higher levels in Kamuli district compared to Masaka and Mukono districts. Thirty-one percent of the ELISA positive samples were confirmed IgG positive by the Western Blot leading to an overall seroprevalence of 2.1% (95% CI: 1.4–3.2%). The large proportion of ELISA positive samples that could not be confirmed using Western blot may be the result of cross-reactivity with other gastrointestinal helminth infections or unknown host-specific immune response mechanisms in local pig breeds in Uganda. Attempts to isolate muscle larvae for species determination using the artificial digestion method were unsuccessful. Due to the large number of muscle samples examined we are confident that even if pigs are infected, the larval burden in pork is too low to pose a major risk to consumers of developing trichinellosis. This was the first large systematic field investigation of Trichinella infection in domestic pigs in Uganda and its results imply that further studies are needed to identify the Trichinella species involved, and to identify potential sources of infection for humans.

Salmonella serovars along two beef chains in Ethiopia

INTRODUCTION Salmonella has been reported from foods and the food production environment, with outbreaks occurring in the human population worldwide. METHODOLOGY A survey on Salmonella in two beef production lines (a beef abattoir line and a processing line) in Addis Ababa, Ethiopia was conducted, with a total of 668 various samples randomly collected from animal-related materials, the environment, and a beef product (mortadella). RESULTS Overall, a 12.9% prevalence (26.3% from the abattoir line, 5.3% from the processing plant line) was observed. The prevalence in the abattoir line environment (36.6%) was higher than that in animal-related samples (14.7%); the reverse was true for the processing plant line. Out of 86 isolates, 10 serovars were identified, and 8 remained unidentified. The predominant serotypes were S. Saintpaul (32.5%), S. Muenchen (19.8%), and S. Larochelle (12.8%). S. Kastrup and S. London were isolated for the first time in Ethiopia. CONCLUSIONS Data indicate open ports of entry for Salmonella, with possible transfer along the line. Further investigations from farm to fork are recommended in order to identify these positions of entry.

Efficacy of knife disinfection techniques in meat processing.

EU Regulation 853/2004 requires that knives used in meat processing be disinfected by submerging them in hot water (+82°C). Alternative procedures are permitted if the efficacy is proved to be equivalent. In the present study, various time-temperature combinations together with pure water, water with lactic acid (2 %), and the use of ultrasound with and without lactic acid (2%) were investigated. Steel plates were covered with fat and protein and then inoculated with a standardized bacterial contamination assembled according to the composition of bacterial contamination found in a previous field trial conducted with regard to the slaughter of pigs. Several combinations with diverse temperatures and time intervals were tested until no microbial load was detectable by using a wet-dry-swab technique that had previously been tested to ensure maximum bacterial recovery. The following were effective in bringing the tested bacterial flora below the detection limit: • 70 °C water bath for 10 s • 60 °C water bath + ultrasound for 5 s • 40 °C water bath + lactic acid (2%) for 10 s • 40 °C water bath + ultrasound + lactic acid (2%) for 5 s In particular, the use of lactic acid permitted a relevant reduction of the temperature, while providing effective sterilization. The use of such non-hazardous food-safe additives is particularly suitable for successful disinfection at lower temperatures.

Fate of sympathetic trunk ganglia after cutting in German meat plants.

To minimize risks from pathogenic prion proteins, particular tissues from bovines and other ruminants have been declared specified risk materials (SRMs), which are required to be removed from the food chain. However, in particular for the sympathetic trunk (ST) as a part of the autonomous nervous system (ANS), which represents a potential transfer route for abnormal prion proteins (PrP(Sc)), this is not the case. Consequently, its destination during cutting procedures deserves attention. In this survey, the handling of the ST in beef cutting plants was recorded during ongoing work. To ease these observations, the ST was separated into five parts, and eight destinations for cuts were identified. By means of an observation sheet, the destination of the respective tissue was recorded. About one-third of the ST went into human consumption, another one-third was disposed of as SRMs, and the last one-third was used for nonfood purposes or disposed of. The rear thoracic and sacral ganglia primarily remained naturally connected to the bones going as SRMs. The stellate, front thoracic, and lumbar ganglia went in a different percent into the food chain. Frequently, workers in the same plant decided differently, even from case to case, on the destination of the tissue, which indicates a lack of standardization.